1. Field of the Invention
The present invention relates to systems for localization and radiotherapy of various cell lines in various anatomic locations. In particular, this invention relates to a system which coordinates proton beam irradiation with an open magnetic resonance imaging (MRI) unit to achieve near-simultaneous, noninvasive localization and radiotherapy of various cell lines in various anatomic locations by maintaining coincidence between the target and the proton beam.
2. Description of the Prior Art
Proton beam irradiation therapy treats tumors found in selected locations that are not subject to significant physiologic motion. Examples of such tumors include prostatic cancer, spinal chordomas, and certain retinal or orbital tumors. The proton beam generated by a medical cyclotron has similar biological activity for the destruction of tumors as standard radiation therapy techniques to target a fixed tumor site with minimal radiotoxicity to the surrounding normal tissues. Because protons of a specific energy have a specific penetration depth, adjusting the specific energy of the protons manipulates the distance the proton beam travels into the patient. Because protons deposit most of their energy at the end of the penetration depth, the highest concentration of radiation occurs in the area around the penetration depth. This area is known as the Bragg peak of the proton beam.
The focused delivery of protons to a fixed site permits the radiotherapy of tumors or the destruction of tissue causing functional problems. However, tumors and tissue located in organs subject to significant physiologic motion cannot be treated without significant collateral radiotoxicity. There is a need for a system which allows proton beam delivery to a target subject to significant physiologic motion that minimizes the collateral damage to the surrounding normal tissues.